Field of Invention
The present invention relates to an electronic device and a control method. More particularly, the present invention relates to a power conversion device, a driving device and a driving method.
Description of Related Art
With the advancement of science and technology, the techniques used by the electronic power industry are maturing; hence, power supply devices are widely applied in various electronic devices. Reliability is a basic requirement for such electronic power devices. A reliable electronic power device can stably operate under normal operating conditions, and can effectively protect itself when malfunctioning, so that the electronic power device will not be damaged.
In applications involving high-power electrical devices (for example, industrial computers, servers, power equipment, and so on), product reliability is extremely high. Mean time between failures (MTBF) is commonly used as a standard for measuring reliability. If the MTBF of an electrical device is large, the reliability of the electrical device is high.
In present-day power supplies of electronic devices, optical fibers are typically used to transmit control signals to high-voltage sides of the output ends of such power supplies so as to control power switching elements in the high-voltage sides. Compared with using electrical connections, performing transmission utilizing optical fibers allows for electrical isolation to be realized between high-voltage sides and low-voltage sides of transforming modules and between each power switching element of the high-voltage sides so as to avoid electrical noise interference therebetween.
However, compared with other electrical devices in a system, in general, the MTBF of an optical fiber transceiver is extremely low, such that optical fibers have become stumbling blocks with respect to enhancing reliability of a system.
Moreover, since each power switch needs to be isolated from the low voltage side and other power switch elements on the same high-voltage side, each power switch element needs a set of optical fibers for transmitting driving signals. Hence, using optical fibers to realize isolation will substantially increase the cost and structural complexity of a system.
In addition, since there is a significant delay time for transmitting signals by optical fibers, the consistency (or synchronicity) in transmitting the same signals is poor. When high consistency is demanded, the reliability of power switch elements will be affected.
Transmitting driving signals using magnetic isolation instead of optical isolation for achieving electrical isolation can enhance the reliability, reduce the cost, and simplify the structure of a system, as well as decrease delay time, and increase the consistency of signals so as to effectively solve the problems caused by using optical isolation.
Transmitting driving signals to switching units connected in series by using magnetic isolation has been used in series driving circuits for driving half-controlled power switch elements. For example, the driving signals of a low-voltage side are transmitted through transformers connected in series so as to transmit triggering pulses with driving ability to a high-voltage side for driving half-controlled power switch elements connected in series. A conventional half-controlled power switch element is, for example, a silicon controlled rectifier (SCR).
Due to the properties of half-controlled power switch elements, the requirements of driving signals for an SCR are that (1) only an extremely narrow pulse is necessary to trigger and turn on an SCR, and a turn-off signal is unnecessary since a half-controlled power switch element cannot be turned off by a driving signal; and (2) since the pulse of a driving signal for a half-controlled power switch elements is narrow, a driving signal and driving power thereof can be transmitted through a pulse transformer simultaneously.
Furthermore, there are many differences between the requirements of driving signals for full-controlled power switch elements and the requirements of driving signals for half-controlled power switch elements. For example, turning on and off full-controlled power switch elements are both performed using driving signals. Moreover, a stable high-voltage level is necessary for turning on full-controlled power switch elements, and a stable low-voltage level is necessary for turning off full-controlled power switch elements. As another example, the pulse width of driving signals for full-controlled power switch elements is wider than the pulse width of driving signals for half-controlled power switch elements (for example, SCR).
Hence, transmitting driving signals of half-controlled power switch elements (for example, an SCR) through magnetic isolation cannot be used in full-controlled power switch elements.
Some electrical devices do not have malfunction detectors; hence, if power electronic devices are malfunctioning, these power electronics devices cannot effectively detect the malfunction, so that these power electronic devices cannot warn users and take any effective protective measures.
Moreover, although some power electronic devices have malfunction detectors, these power electronic devices transmit malfunction signals through optical isolation elements, such that manufacturing costs are increased and reliability is decreased.
In view of the foregoing, problems and disadvantages are associated with existing products that require further improvement. However, those skilled in the art have yet to find a solution.